In a color photographic process a color photographic light-sensitive material is exposed to light, and then subjected to color development so that an oxidation product of an aromatic primary amine developing agent reacts with a coupler to form an image on the material. In such a process, a subtractive color process is used for color reproduction, where in order to reproduce blue, green and red images, there are formed yellow, magenta and cyan images, which respectively are complementary thereto.
Couplers are basically required not only to form colors but also to exhibit various excellent properties. For example, dyes developed from couplers should have excellent spectral absorption characteristics. Further, couplers should develop dyes at a high rate, and these dyes should provide a high color density. Dyes thus developed from couplers should exhibit a high fastness to heat, light and moisture. In recent years, since the markets have demanded a photographic light-sensitive material with a higher sensitivity and a higher image quality, than conventional materials. It has been keenly desired to develop a coupler which can form a dye at a high rate and provide a high color density. Further, in the design of DIR couplers (i.e., couplers which react with an oxidation product of an aromatic primary amine developing agent to release a development inhibitor and thus are used for the purpose of improving image sharpness and color reproducibility), the aforementioned properties can be important factors. In the case of yellow couplers, one effective approach for enhancing the rate at which dyes are formed is to introduce an acidic separatable group or high polarity group into the coupler molecule. Examples of such an approach include the introduction of a p-hydroxybenzenesulfonyl group or p-hydroxybenzenesulfinyl group as described in U.S. Pat. No. 4,443,536, and the introduction of an N-acylsulfamoyl group as described in British Patent 909,318, U.S. Pat. No. 4,617,256, and JP-B-62-61251 (The term " JP-B" as used herein means an "examined Japanese patent publication"). However, these prior approaches leave much to be desired.